It is desirable to have a door closer which will produce sufficient force to reliably close and latch the door. In addition, upon opening, it should present a relatively uniform force from the closed position to the open position. In a door closer application there is a substantial geometry change from the point of attachment of the control arm on the door controller to the door frame track where the force is applied in going from the closed position to the open position. This is further complicated in that the force produced by the closer generally increases as the door opens because of internal spring rates in the closer. As a result there is considerable variation in the force necessary to open the door and conversely the force exerted by the closer in closing the door varies substantially over the range of door opening.